Rock Identifier
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2) — mineral
mineral

Lepidolite

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Hardness: 2.5-3 (Mohs scale); Color: Pink, lilac, purplish; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal; Specific gravity: 2.8-2.9

Hardness
2
Color
Pink, lilac, purplish
Luster
Vitreous to pearly
Identified More mineral

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Physical properties

Hardness: 2.5-3 (Mohs scale); Color: Pink, lilac, purplish; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal; Specific gravity: 2.8-2.9

Formation & geological history

Formed in granitic pegmatites during the late stages of crystallization; usually occurs with other lithium-bearing minerals like tourmaline and spodumene.

Uses & applications

Major source of lithium; used in glassmaking and ceramics to prevent thermal expansion; also popular for jewelry (cabochons) and as a decorative stone.

Geological facts

Lepidolite is known as the 'peace stone' in folklore and is a primary source of the rare alkali metals rubidium and cesium.

Field identification & locations

Identify by its distinctive lilac color, micaceous layering, and low hardness (can be scratched by a copper coin). Found in Brazil, Madagascar, and the USA (California, Maine).